OB Nursing: Fetal Heart Monitoring – Part 5

In this part of OB nursing, we’ll discuss fetal monitoring with pregnant women who are in labor.

Whether it’s a client coming into the labor room, or someone who’s had her water broken, or even anytime that you are required to do a fetal assessment, this is what you’ll need to do.

To begin with, there will be two monitors placed on the mother’s belly; one will measure the contractions while the other will measure the fetal heart rate or fetal heart tones. Focusing on the fetal heart rate, there are certain classifications that tell whether the heart rate is:

  • Reassuring
  • Elevated
  • Early deceleration (bradycardic)
  • Late deceleration (severely bradycardic)

Classification 1: Reassuring

In reassuring, the egg cells last for 15 beats per minute over a period of 15 seconds. This means that there is baseline of 140 which goes up then goes back down. So that’s 15bpm. This is similar to a reactive stress test. If there are two accelerations, it just means that your baby’s moving which makes the heart rate go up.

Classification 2: Elevated heart rate

How can you spot an increased heart rate? The baseline is usually above 160. This is now referred to as tachycardia. Here, there’s inadequate blood supply that can either be caused by a lot of factors like drugs, medication, or infection. Any type of external stressor or sepsis (infection) can cause elevated heart rate. Tachycardic babies can show a heart rate of 180 and can even reach as high as 200.

To confirm the presence of infection, the doctor might order an amniocentesis to take samples of amniotic fluid and trace where the infection started inside the body.

Classification 3: Early decelerations

What you have to remember with early deceleration is that the baby’s heart rate goes down as the mom’s goes up. The mom’s uterus is contracting to push the baby out thereby dilating the cervix to 10cm. All that pressure that the uterus is doing on the amniotic sac is causing the placenta to become stressed, thus the decrease in the baby’s heart rate. After that quick dip, the baby’s heart rate will return to its normal baseline with contractions.
Early decelerations are good. Remember, it’s good to be early.

Classification 4: Late decelerations

If there’s good, there’s definitely bad. Late decelerations are the worst classification of fetal heart rate because as previously mentioned, after contraction, the baby’s heart rate should immediately return to its baseline. Late decelerations occur when the baby’s heart rate does not return to normal. What you’ll see on the monitor are fluttering lines, like a bird flying down or a staircase.

Possible indications for this would be oxygen depletion with decreased uterine blood flow; there might be an insufficient placenta, possibly placenta previa. Interventions for late decelerations are:

  1. Lower the head of the bed and turn the mom on her left side to take the pressure off the vena cava and allow blood flow to the heart and to the lungs. Note: This is a key nursing intervention so you have to keep this in mind.
  2. Re-oxygenation or the reintroduction of oxygen to the baby by giving oxygen to the mother. Give about six liters of oxygen.

This intervention will allow re-perfusion to the uterus and manage late decelerations.

In cases that standard interventions don’t work and late decelerations are still showing, the best way to deal with this is through a C-section. This is because you have a de-oxygenated baby that is getting too little oxygen who is going to die. Once the baby is out of the womb, resuscitation will follow.

So, that’s it for fetal heart rate monitoring. Check out our previous OB nursing lectures from part 1 until part 4 in our other videos and web pages by visiting SimpleNursing.com.